Tempest not detected fog

My Tempest never detects fog in the air why? never notice I get fog

not sure what you mean by detect. Fog isn’t like rain or so and there is no alert for fog.

Your Tempest seems to work ok, though I see high levels of humidity pretty constant. Maybe you’re in a very humid region or lots of rain these days. Or maybe to close to vegetation, that can explain these high levels of humidity.

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Thanks Eric !
I thought there would be a notice

if the humidity shows 100% can we say that it is fog?

Not really. 100% RH is not the only thing needed to indicate foggy conditions. For example, this morning’s conditions at a nearby airport’s ASOS this morning ( https://www.wrh.noaa.gov/mesowest/timeseries.php?sid=KPTW&wfo=fgz&num=72&hfmetars=1 ) shows a string of readings where the RH is 100% but, visibility is at 8 miles.

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Look at the dew point and current temperature. If they are the same then there is likely fog.

As wx3i09 pointed out in above post… that is not necessarily true.

I did say there is likely fog, not a guarantee of fog. With the data shown above it is entirely possible that the temperature is 34.4F and the dew point is 33.5F. If I were planning a flight to that airport I would definitely assume it was going to be foggy when I arrived as that would be the safest assumption, especially when flying VFR.

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You can say whatever you like. You can say it’s ice cream but that doesn’t make it true.

No… you cannot say it is fog.

He has my permission and he has freewill so I’ll let him do as he likes.

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I am trying to not get too deep into this, but, the numbers I showed from that site were fahrenheit representations of mostly five minute obs ( which are really specified in °C using whole numbers, but, that site converts them to °F using whole numbers), so, there is some potential for rounding errors when converted to °F . But, the obs produced at the “synoptic hours” include T/Td in °C to one decimal point. These are also available at that site and are logged at hh:54 for this particular station.

From an aviation viewpoint, yeah … plan for fog. But, in cases like this morning (and many mornings), the nocturnal inversion can result in a very thin saturated layer very close to the ground, but, fog does not result, because just above that layer is a layer that is warmer and drier (and the gradients are often very sharp), so, fog does not result because of the mixing that occurs between these layers. At my example station, there was likely a pronounced thermal inversion (as indicated in forecast soundings). Fog was not in the forecast for the area nor was any observed in the area as far as I know.


I expect from the Tempest weather station that it will soon be able to resolve the notification with the new firmware and for the fog I hope it will be soon that we have a notification when the fog

Well … since the Tempest has no atmospheric sounding equipment to determine the thickness of the saturated layer (and other information), or an optical instrument to measure visibility, it is unlikely that this capability will become part of the unit.


exactly the point I was trying to make… you did a nice job

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Perhaps at some point in the future you can get a forecast for fog, but the device doesn’t measure if there actually is fog, so it will not be able to generate a notification that it detected fog.

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